1. Field of the Invention
This disclosure generally relates to installable members and methods of installing the members in an opening of a workpiece.
2. Description of the Related Art
Conventional solid lubrication lined or coated bushings, bearings, or the like are utilized for a variety of applications and in a variety of industries. These bushings and/or bearings are generally referred to as “self-lubricating” bushings and/or bearings and are employed where lubricant cannot be supplied continuously or repeatedly. One type of self-lubricating bearing is a KARON® bearing manufactured by Kamatics Corporation, which is a subsidiary of Kaman Corporation. The KARON® bearing includes a machinable self-lubricating liner system that resists swelling.
Self-lubricating bushings and/or bearings are typically installed into an opening of a structural workpiece by either press fit techniques or conventional freeze (i.e., shrink) fit techniques. Both of these techniques permit the self-lubricating bushing and/or bearing to be installed without causing damage to the inner diameter surface, which may be a soft lubricated liner or may be silver-coated, for example.
The process of shrink fitting includes sufficiently cooling the bushing and/or bearing in cryogenic fluid to reduce the outer diameter and rapidly placing it into the structural workpiece. Alternatively, the process of press fitting is where the bushing and/or bearing has a slightly larger outer diameter than the diameter of the receiving opening, and the bushing and/or bearing is forced into the opening. One drawback of both of these processes is that they cause damage to structural material surrounding the opening. Another drawback is that the amount of interference fit is limited because of a number of factors. In shrink fitting, for example, the temperature may not be low enough to sufficiently shrink the outer diameter of the bushing or bearing or the installation may not be fast enough to place the bushing or bearing before the outer diameter returns to the normal size at ambient temperature (e.g., the operating temperature). In press fitting, the tolerances between the bushing and/or bearing and the opening in the structural workpiece will vary, which may result in at least some assemblies not achieving a desired amount of interference. In addition, press fitting is typically limited to being used on smaller assemblies; otherwise the pressing forces exceed the capabilities of even large mechanical presses. These drawbacks, in turn, may lead to manufacturing difficulties, increased manufacturing costs, in-service problems, and/or degraded operational performance of the components that were fit together.
One option for installing bushings and/or bearings, especially in components that will undergo repetitive load cycles and/or may be susceptible to accumulating fatigue damage, is the FORCEMATE® installation method developed by Fatigue Technology, Inc. The FORCEMATE® installation method utilizes a tapered mandrel installed in a puller tool, for example, to pass the mandrel through an initially clearance fit bushing that has been positioned in the opening of the structural workpiece. The tapered mandrel radially expands the bushing into the opening to obtain a controlled and consistently higher interference fit than would be achievable by either the shrink or press fit processes. In addition, the FORCEMATE® installation method induces beneficial residual compressive stresses into the structural material surrounding the opening, which may advantageously extend the fatigue life of the component, assembly, or installation. The FORCEMATE® installation method, as well as other cold-working methods; tooling, and the like, such as the BUSHLOC®, FORCETEC®, and FLEXMATE® methods are described in U.S. Pat. Nos. 3,566,662; 3,892,121; 4,187,708; 4,423,619; 4,425,780; 4,471,643; 4,524,600; 4,557,033; 4,809,420; 4,885,829; 4,934,170; 5,083,363; 5,096,349; 5,405,228; 5,245,743; 5,103,548; 5,127,254; 5,305,627; 5,341,559; 5,380,136; 5,433,100; and in U.S. patent application Ser. Nos. 09/603,857; 10/726,809; 10/619,226; and 10/633,294.
The FORCEMATE® and other installation methods identified in the preceding paragraph have been found to be less than optimal for installing self-lubricated bushings and/or bearings because the operation of passing (e.g., pushing or pulling) the mandrel through the bushing and/or bearing may damage the lubricated liner and/or coating. To limit such damage, the amount of radial expansion must be reduced, however this results in less than optimum fatigue life enhancement of the surrounding structure and less than optimum fixity between the bushing or bearing and the structure.
Based on the foregoing, it is desirable to have an installable component (e.g., a bushing, fitting, fastener, bearing, and the like), an assembly, or a kit, as well as method of installing the same. Benefits of cold expansion of the structural workpiece can be achieved while minimizing, reducing, limiting, or substantially preventing damage the self-lubricated component, bearing, or like device.